Guidance about tailings storage

Tailing storage facilities (TSFs) are reservoirs that store mine tailings, which is fine-grained waste material in suspension that is discharged from an ore processing plant or coal preparation plant. Inappropriate storage of tailings can lead to safety, health and environmental hazards.

The department has produced a code of practice to assist industry to store and manage tailings, and to meet their legislative obligations for work health and safety under the Mines Safety and Inspection Act 1994 and environmental matters under the Mining Act 1978.

The aims of this code are to describe:

• a set of outcomes for TSFs to meet the approval requirements of the project management plan under legislation
• the variables to be considered to demonstrate that a TSF is safe, stable, non-polluting, erosion-resistant and self-sustaining
• the recommended hazard management process for TSFs
• the broader occupational health and safety requirements for operating in accordance with legislation.

The code promotes a proactive approach to monitoring during construction, operation, and prior to closure so it is possible to predict a TSF’s long-term performance and potential environmental impact after closure.

A high impact function (HIF) audit is available to address features associated with the life cycle of a TSF.

Guides

The Environment and Resources Safety Divisions have prepared two guides to assist TSF designers and operators with the preparation of the required reports for managing a TSF. The guides describe the reports that should be submitted to the Department in accordance with section 4 of the Mining Proposal guidelines as required by the Mining Act 1978 and referenced in Tailings storage facilities in Western Australia - code of practice.

While there is no format specified for these reports, certain information is required in order to assure the department that a TSF can be managed safely. Using the guides ensures the information is supplied in a format that meets requirements.

Management and closure of TSFs

Design report

The design report is a more complex and detailed report that presents an analysis of the background conditions and investigations undertaken when planning the TSF. The report outlines the basis of the design and justifies the parameters adopted for the engineering design, construction, operation, rehabilitation and after closure of the TSF.

Tailings storage facilities in Western Australia - code of practice

The Australian National Committee on Large Dams Incorporated (ANCOLD) has produced a number of relevant guidelines, including:

• Guidelines on tailings dams - Planning, design, construction, operation and closure (2012)
• Guidelines on the consequence categories for dams (2012)
• Guidelines for dam Instrumentation and monitoring systems (1983)
• Guidelines on risk assessment (2003)

The International Commission on Large Dams (ICOLD) has produced a number of relevant bulletins, including:

• Bulletin 153 Sustainable design and post-closure performance of tailings dams (2013)
• Bulletin Preprint-151 Tropical residual soils as dam foundation and fill material
• Bulletin 139 Improving tailings dam safety - Critical aspects of management, design, operation and closure (2011)
• Bulletin 121 Tailings dams risk of dangerous occurrences - Lessons learnt from practical experiences (2001)
• Bulletin 106 A guide to tailings dams and impoundments - Design, construction, use and rehabilitation (1996)
• Bulletin 104 Monitoring of tailings dams - Review and recommendations  (1996)
• Bulletin 103 Tailings dams and environment - Review and recommendations  (1996)
• Bulletin 101 Tailings dams. Transport. Placement. Decantation - Review and recommendations (1995)
• Bulletin 98 Tailings dams and seismicity - Review and recommendations (1995)
• Bulletin 97 Tailings dams - Design of drainage (1994)